It seems to be a combination of factors on most trucks.
A buddy of mine brought his truck over and we did a leveling kit. He was going to change out the steering stabilizer at the same time and it was the wrong kit. He chose to drive home without the stabilizer and death wobble happened at every bridge bump. Put it back on, DW dissapeared.
Other factors, oversized tires that do not have enough sidewall strength and or air pressure to resist rolling under and bouncing. 'E' range tires should be considered mandatory.
Camber/ caster angles are a biggie and usually, you can rotate the axle enough in your driveway to stop DW.
Obviously, as suspension and steering components age, they can all contribute. Don't forget shocks and the most overlooked component, the ball joint.
I have heard of one truck that replacing the arms helped with DW. Come to find out, the front end was NEVER aligned correctly. So, after about 10K and the new arms, DW came back. 10 minutes on his back under the front end and it wass stamped out and has not come back for 50K.
Also, aftermarket wheels with too little backspacing coupled to a big tire will cause this. I know full well what DW is. I have had it on more than one solid axle rig. And the Dodge is a dream compared to my old Bronco. I learned my lessons there. If you want big tires, stuff a big whell in it. Rides rougher, but handles far better. And keep those wheels close to the steering arm. You'll be much happier!!
Dave